A perl5 source filter implementation of the perl6 yada operator '...'.
Update - added '!!!' which is a closer perl6 implementation of '...'
Update 2 - added '???' re tye's node Re: the 'dot dot dot' operator (s/the/another/), also the native '...' becomes the new '...' when this code is used 
package dotdotdot;

use Filter::Simple;

FILTER_ONLY
  code => sub {
  s{ \s \Q...\E \s }{ () }gx;};
  s{ \s   !!!   \s }
     { die("Deferred implementation can't be executed"); }gx;
  s{ \s \Q???\E \s }
     { die("Deferred implementation can't be executed"); }gx
};

q[ foo bar baz ];

[download]

Replies are listed 'Best First'.
Re: the 'dot dot dot' operator (s/the/another/)
by tye (Sage) on Apr 14, 2003 at 16:09 UTC

    Um, ... is already an operator in Perl5. You should at least document that one can't use that anymore if one uses your module. See Re: My day with Damian Conway.

    For the record, I'd rather have !!! and/or ??? instead of ... as I find their visibility much more in line with their importance (and for the reason given in my reply under the node I linked to above).

                    - tye
[reply]
[d/l]
      Um, ... is already an operator in Perl5.
      Doh! Of course it is :-/
      For the record, I'd rather have !!! and/or ??? instead of ... as I find their visibility much more in line with their importance
      I'll second that. I find ... a little too innocuous looking for an operator which will throw an error unconditionally if executed. So ??? is probably the way to go since it's a syntax error if left unfiltered.
      HTH

      _________
      broquaint

[reply]
Re: the 'dot dot dot' operator
by diotalevi (Canon) on Apr 14, 2003 at 14:04 UTC

    How about instead of () you insert die("Deferred implementation can't be executed");.

[reply]
[d/l]
[select]
      How about instead of () you insert die("Deferred implementation can't be executed");.
      Perhaps, but when I used it I just wanted a placeholder, not necessarily an abstract op (yes, I made that up ;) and I also have no idea how it will be implemented in perl6 (it may be described in p6l ... somewhere). Maybe we need YAO instead 
      package bangbangbang;

use Filter::Simple;

FILTER_ONLY
  code => sub {
    s{ \s \Q!!!\E \s }
     { die("Deferred implementation can't be executed"); }gx
  };

q[ ichi ni san ];

      [download]
      And obligatory example usage 
      use bangbangbang;

sub foo { !!! }
my $bar = sub { !!! };
sub baz { return !!! }

eval { foo()   } or warn "foo() - $@";
eval { &$bar() } or warn "bar() - $@";
eval { baz()   } or warn "baz() - $@";

__output__

foo() - Deferred implementation can't be executed at bbb_test.pl line 
+3.
bar() - Deferred implementation can't be executed at bbb_test.pl line 
+4.
baz() - Deferred implementation can't be executed at bbb_test.pl line 
+5.

      [download]

      HTH

      _________
      broquaint

[reply]
[d/l]
[select]

        It occurs to me that I dislike bang-bang-bang because that conflicts with the common idiom bang-bang to booleanize something. Also, I recall dot-dot-dot being proposed elsewhere as a fatal op which on being executed warns that something wasn't complete and it shouldn't have been executed.

[reply]

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